I recently got a check & 4,000 bonus miles offer from AT&T (unfortunately, it was only $20 but better than nothing).

Here's a tip, though: when I called up to switch, I asked if there were any other plans available besides the $5.95 a month plan, and I was able to get a plan with no monthly fee ($5 minimum) & 9 cents a minute. This is pretty good for people like me who never actually make calls but need the miles! Give it a try!